Battery electric vehicles, extended-range electric vehicles, and hybrid electric vehicles each use a rechargeable high-voltage energy storage system (ESS), e.g., a rechargeable battery, to deliver electrical power to one or more traction motors. The traction motor(s) alternately draw power from and deliver power to the ESS as needed. When propelled solely using electricity, the operating mode of the vehicle is referred to as an electric-only or EV operating mode.
In a hybrid electric vehicle design, an internal combustion engine may be used to generate torque suitable for propelling the vehicle in various operating modes. An extended-range electric vehicle uses an engine having a reduced size to selectively power a generator, which in turn delivers electricity to the traction motor either directly or via the ESS. Such a decoupled engine configuration can extend the effective EV range of the vehicle after the state of charge of the ESS becomes substantially depleted.
Vehicles that use an engine for direct mechanical propulsion or for generating electricity may employ an engine-driven main fluid pump to deliver fluid under pressure to a transmission. Clutches, valve bodies, gear sets, and other lubricated components are thus provided with a reliable supply of fluid during any engine-on operating modes. However, the engine-driven main pump may be unavailable when the vehicle is traveling in an EV mode. Battery-electric designs lack an engine, and therefore an engine-driven main pump. Therefore, an electrically-actuated fluid pump may be used to circulate fluid in an EV mode-equipped vehicle.